1. Field of the Invention
The present invention relates to an endoscope in which the distal portion of the insertion part is provided with an endoscope observation mechanism.
2. Description of the Related Art
Endoscopes are configured such that the insertion part composed of a flexible portion, a bending portion, and a distal portion is provided so as to be connected to a main body operating part, and an endoscope observation mechanism is provided at the distal portion. Among these endoscopes, an endoscope is disclosed in JP2007-252458A. In this JP2007-252458A, an endoscope observation mechanism is of an oblique-front-viewing type in which the observation visual field is set to be obliquely forward.
When ultrasonic scanning is performed within the body of a subject by using an ultrasonic transducer which constitutes an ultrasonic observation mechanism, if an affected part or a part suspected to be an affected part is detected, this is used as a region of interest, living cells of this region of interest are sampled, and treatment, such as injection of a medical fluid is performed as necessary. For this reason, a puncture treatment tool is used. The puncture treatment tool is configured such that a hard pipe having a predetermined length is provided so as to be connected to the distal portion of a catheter, and the tip of this hard pipe is formed as a sharp needle point. Here, the puncture treatment tool is led out of a treatment tool outlet provided in the distal portion. However, in order to perform the lead-out under the observation by an endoscope observation mechanism and an ultrasonic observation mechanism, the puncture treatment tool has the oblique frontal lead-out direction.
In order to lead out various kinds of treatment tools including the puncture treatment tool, a treatment tool insertion channel is provided within an insertion part. In this case, a treatment tool insertion tube made of a flexible member in the bending direction is provided inside a flexible portion and a bending portion in the insertion part. The distal portion is provided at this distal end body, and a treatment tool insertion passage is bored in the distal end body. The treatment tool insertion tube and the treatment tool insertion passage are connected together by a connection pipe made of a hard member. Here, since the treatment tool insertion tube extends in the axial direction of the insertion part, and the treatment tool insertion passage is a passage which is directed to the oblique frontal direction in the distal end body, the connection pipe is made of a bending pipe, and thereby the treatment tool insertion tube which extends in the axial direction of the insertion part is changed in direction so as to face the oblique frontal direction.
An endoscope observation mechanism in an endoscope (hereinafter referred to as an ultrasonic endoscope) including an ultrasonic observation mechanism is constituted by an illumination portion and an observation portion. An emitting end of a light guide which transmits the illumination light from a light source unit faces the illumination portion. The observation portion disclosed in JP2007-252458A is configured such that a lens barrel with mounted objective lenses is mounted on a distal end body, a prism is connected to the proximal end of this lens barrel via a prism holder, and a solid state imaging element and its printed circuit board which serve as imaging sections are fixed and provided to the prism. A plurality of signal cables is connected to the printed circuit board, these signal cables are bundled, and are extended to a universal cord, which is provided so as to be connected to a main body operating part, via the main body operating part from the insertion part. In this way, the lens barrel provided with the objective lenses, the prism holder and the prism, the solid state imaging element and its printed circuit board which are imaging sections are unitized and constituted as an observation unit. The observation unit is inserted into the mounting hole bored in the distal end body, and is fixed and held by means such as adhesion. The lens barrel is inserted into this mounting hole, and the prism holder, the prism, and the imaging sections do not have special fixing portions, and are fixed to the distal end body via the lens barrel.